Fixing element for double glass plates

ABSTRACT

A fastening element for doubleglass panels has a threaded bolt having a forward end and provided with an expansion cone at the forward end, an annular expansion element pushed onto the expansion cone for expansion in a hole drilled in a rear glass panel and provided with an undercut in a region of a bottom of the drilled hole, a cap placed on the expansion element and resting against an end face of the threaded bolt, and a spacing sleeve arranged on a shank of the threaded bolt so as to rest against the rear glass panel and to pass through a front glass panel, the spacing sleeve having a portion engageable in the hole drilled in the rear glass panel and providing an abutment for the expansion element.

BACKGROUND OF THE INVENTION

The Invention relates to a fastening element for double glass panels.

DE 40 11 229 discloses a fastening element for anchoring in a facingpanel, which fastening element consists of a threaded bolt having anexpansion cone arranged at its forward end, onto which expansion conethere can be pushed an annular expansion element. In order to preventthe fastening element from coming out of the drilled hole when it isbeing anchored in the thin-walled facing panels, anchoring takes placein an undercut drilled hole, allowing high pull-out loads whilst theanchoring is virtually free of pressure of expansion.

In order to centre the threaded bolt in the drilled hole, a spacingelement is provided, which at the same time ensures that the expansionelement pushed onto the expansion cone is not displaced. The spacingelement has a flange, which rests against the external surface of thefacing panel, as a result of which the fastening element is tensionedwhen a nut is screwed up on the threaded bolt; the tensioning providessupport for the fastening element so that transverse forces are takenup.

Because of the high tensioning force required to provide support for thefastening element, on the one hand, and because the expansion element,which is made from metal, bears directly against the wall of the drilledhole, on the other hand, the known fastening element is not suitable forfastening double glass panels, for example for cladding buildings.

SUMMARY OF THE INVENTION

The invention is accordingly based on the problem of providing afastening element that is suitable for anchoring in glass panels and forthe fastening thereof.

When the fastening element is designed in accordance with the presentinvention, it eliminates the above mentioned problem.

By means of the cap, which is made from soft plastics material and whichis placed over the end face of the threaded bolt and the expansionelement, direct contact between the expansion element, which is madefrom steel, and the glass surface is avoided. The cap, which is, forexample, made from polyurethane, is resiliently and/or plasticallydeformable so that rigid loading at a point, which can in certaincircumstances result in the glass breaking, is replaced by soft,irregularity-compensating loading over an area. Because of the resultingmore uniform distribution of pressure over a larger area, high loadingvalues can be achieved with the fastening element according to theinvention, even in glass.

The portion engaging in the hole drilled in the rear glass panel andproviding an abutment for the expansion element forms a shoulder on thespacing sleeve, which shoulder rests against the rear glass panelwithout exerting pressure. The spacing sleeve passes completely throughthe front glass panel so that, when the nut is screwed up for fixing thefastening element, the force of reaction is completely taken up by meansof the spacing sleeve. Because there are no pressure forces acting oneither the rear or the front glass panel when the fastening element isbeing anchored, the fastening element according to the invention issuitable for fastening double glass panels wherein the two panes arearranged spaced apart from one another. Because the spacing sleeve isgiven support by means of the portion engaging in the hole drilled inthe rear glass panel and by its outer surface in the hole drilled in thefront glass panel, the spacing sleeve also assumes the task of taking uptransverse forces acting on the double glass panel.

In a further embodiment of the invention, the spacing sleeve can have aflange lapping over the hole drilled in the front glass panel. Thespacing between the underside of the flange and the shoulder of thespacing sleeve resting against the rear glass panel is so selected that,when the fastening element is tightened, no pressure is exerted on thefront pane of glass. The flange serves merely for additional sealing ofthe hole drilled in the front pane of glass and to extend the area forthe nut to rest against. In order to improve sealing, one or moreannular sealing ribs can be arranged on the underside of the flange.Such sealing, which can optionally be further improved using appropriatesealing means, is especially advantageous when the fastening element isused for fastening insulating glass panels.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail hereinafter with referenceto an exemplary embodiment illustrated in the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The fastening element 1 consists of a threaded bolt 2, which has anexpansion cone 3 at its forward end and a thread 4 at its rear end. Onthe expansion cone 3 there is arranged an expansion element 5, which ispressed onto the expansion cone 3 for the purpose of anchoring thefastening element 1 in the rear glass panel 6 of a double glass panel 7.In the exemplary embodiment shown, the expansion element 5 is pressed onby screwing up the nut 8 on the threaded portion 4 of the threaded bolt2. When the nut 8 is screwed up, the cap 9 of soft plastics materialplaced over the expansion element 5 and the end face of the threadedbolt 2 is compressed between the expansion element 5 and the wall of theundercut 10 of the drilled hole 11 so that direct contact between theexpansion element 5, which is made from steel, and the glass surface isavoided.

The threaded bolt 2 passes completely through a spacing sleeve 12 ofhard plastics material, a portion 13 of which engages in the hole 11drilled in the rear glass panel 6. This portion 13, which has a smallerdiameter than the spacing sleeve 12, forms a shoulder 14, by means ofwhich the spacing sleeve 12 rests against the rear glass panel. Thespacing sleeve 12 passes completely through the front glass panel 15,which has a drilled hole 16 corresponding to the external diameter ofthe spacing sleeve 12. For lapping over the hole 16 drilled in the frontglass panel 15, there is arranged on the spacing sleeve 12 a flange 17,which on its underside is provided with an annular sealing rib 18 forimproving the sealing. At the same time, the flange 17 serves as anabutment for the nut 8 in order to avoid direct contact with the glasspanel 15. By means of the projecting end of the threaded bolt 2, thedouble glass panel 7 can be fastened to a substructure for the purposeof cladding a wall of a building (not illustrated).

What is claimed is:
 1. A fastening element for doubleglass panels,comprising a threaded bolt having a forward end and provided with anexpansion cone at said forward end; an annular expansion element pushedonto said expansion cone for expansion in a hole drilled in a rear glasspanel and provided with an undercut in a region of a bottom of thedrilled hole; a cap placed on said expansion element and resting againstan end face of said threaded bolt; and a spacing sleeve arrangedon ashank of said threaded bolt so as to rest against the rear glass paneland to pass through a front glass panel, said spacing sleeve having aportion engageable in the hole drilled in the rear glass panel andproviding an abutment for said expansion element, wherein said cap andsaid spacing sleeve are composed of plastic materials such that aplastic material of said cap is softer than a plastic material of saidspacing sleeve.
 2. A fastening element as defined in claim 1, whereinsaid spacing sleeve has a flange operative for lapping over the holedrilled in the front glass panel.
 3. A fastening element as defined inclaim 2, wherein said flange has an underside provided with at least oneannular sealing rib.